Comparative Studies on Related Free‐Living and Pathogenic Amebae With Special Reference to Acanthamoeba*

Abstract

Comparative studies were conducted on the structure, nutrition, protein composition, immunology, and effect on cell cultures of Acanthamoeba sp. (Lilly A-1 strain), A. castellanii (Singh and Neff strains), A. astronyxis, A. comandoni, A. polyphaga, A. terricola, Hartmannella vermiformis, and Naegleria gruberi. Lilly A-1 strain of Acanthamoeba received special attention owing to its pathogenicity for experimental animals. Distinct differences were noted in structure, nutrition, and antigenic composition of Acanthamoeba spp. and Hartmannella, and it was concluded that their recognition as separate genera is justified. With the exception of A. terricola, all species of Acanthamoeba could be differentiated by cyst structure. Cysts of A. terricola closely resembled those of A. castellanii Singh strain, and close antigenic relationships between these 2 species were demonstrated by gel diffusion and immunoelectrophoresis (IEP); it was concluded that the 2 amebae belong in the same species. The pathogenic Acanthamoeba sp, Lilly strain differed from the nonpathogenic A. castellanii Singh strain (a) cyst structure; (b) protein distribution patterns (on disc electrophoresis);(c)soluble and particulate antigens (on gel diffusion, IEP, complement fixation, and immobilization tests); (d) capacity to induce cell-free plaques and other cytopathic effect (CPE) in mammalian monlayer cell cultures; (e) elimination of a phospholipase, responsible for some of the CPE, into the culture medium. Acanthamoeba sp. Lilly strain, which liberated more phospholipase, produced more CPE. Acanthamoeba sp. Lilly strain differed also from other species of this genus in cyst structure and antigenic composition. It was concluded, therefore, that, following the recommendation of Singh & Das, it ought to be placed in a separate species, Acanthamoeba culbertsoni.

Interaction ofBlastomyces dermatitidis,Sporothrix schenckii, andHistoplasma capsulatumwithAcanthamoeba castellanii

“…A. castellanii is an environmental soil amoeba that feeds on bacteria and fungi for sustenance and also serves as a host for both bacterial and fungal pathogens (30,39). Since thermally dimorphic fungi are found primarily in the soil, we hypothesized that A. castellanii and other environmental phagocytic predators could place selective pressures on soil fungi.…”

Survival of Acanthamoeba Cysts after Desiccation for More than 20 Years

“…The agar plates that were retrieved from storage were dry and parched, and either the entire agar layer or part of the agar layer had detached from the surface of the petri dish. The Parafilm wrappings were removed and 10 ml William Balamuth saline (24), a modified ameba saline, was added to each plate. The plates were allowed to rehydrate overnight, the agar surface was scraped with a cell scraper, and the scraped materials were transferred to 50-ml centrifuge tubes.…”

Apoptosis of Primary-Culture Rat Microglial Cells Induced by PathogenicAcanthamoebaspp

“…B. Jardin of Belgium in 1977) were axenically cultured at 37°C in medium containing proteose peptone, yeast extract, and glucose (23). The degrees of virulence of the two Acanthamoeba spp.…”